Machine for winding resistance coils



' 1,627,188 May 1927' E. N. LIGHTFOOT MACHINE FOR WINDING RESISTANCE COILS Filed April l4. 1920 2 Sheets-Sheetl INVENTOR z m mil- 670 ATTORNEY May 3, 1927. 1,627,188

E. N. LIGHTFOOT MACHINE FOR WINDING RESISTANCE COILS Filed April 14. 1920 2 Sheets-Sheet H 1m H k Ni||||||||||l|||||l|||l|llll lllllllllIHIIIIIIIIIIIIIIIIIIIIIIIIHH! m;

ATTORNEY Patcnted May 3, 1 9 27.

UNITED. STATES.-

n'. Lmnrroor, or amw max, is. I. so, or nmw auxns, wrsoonsm,

, ASSIGNOR TO THE CUTLEB'KAIIMEB MFG.

A COBIOBATIONQF WISCONSIN.

norrmn Ion wmn'mo nasrsranon cons.

' Application fled April 14,

This invention relates to machines for windin resistance coils. p An ofiijectof the invention is to provide an improved'machine for winding resistance coils whereby the wire-wastage is reduced to [a minimum. f When re istance coils are woundby windingonto a supporting spool the number of ca culated turns of wire toproduce a coil of predetermined resistance, frequently the resistance of the coils so produced isless than the predetermined value. This is due to variations in composition andsize of'the wire. Furthermore, due to the variations in l5 the'w'ire it is practically im ossible. to'determine in advance the num r of turns of 'wire to roduce a coil-of the required resistance. t becomes necessar therefore to wind on more than the calcufated number of turns to insurethat a coil of the required resistance is produced. The resistance of such coils must-then be measured and the surplus turns removed. -Such practices not only result in wastage of the wire, but re- 25 quilrse needless and expensive handling of the 001 The improved machine for winding resistance coils according to the presentinvention avoids this rehandling of the coils after .once wound and the wastage of wire. "-One embodiment of this invention is ,lustrated in the accompanying drawings, in

which:' I

. Figure 1 is a top plan of the winding ma.- chine.

Fig. 2 isaf'front elevation of the machine shown. in .Fig. 1. a Fig. 3 is a wiring diagram of electrical connections between the windin machineand cooperatin Wheatstone bri e-circuit. Fig. 4 is. a ragmenta view s owin a modified form of thedevice illustrated iagrammatically in Fig. 3.

Asshown m the drawings, the winding machine. comprises in general, a lathe in the resistance wire is 'to be wound, and associated with which is a-Wheatstone br dge circuit, one arm' of which contains an ele- '12 passes over the which may be mounted a spool upon which wound evenly anon ma, serial. no. erase-1.

havinguprights 8 and 9 joined at the top by a cross head 22. A shaft 10 is jou'rn'aled in the upright 8. A driving pulley 11 is J I secured to"one end of the shaft 10, and. a gear 15 'issecured to the other end. A belt.

pulley 11 for driving the shait 1Q. 7 A splndle 19 is'journaled in the upright 9 and is in alignment with the drivin shaft 10. A clutch 20 is slidably mounte upon one end of the spindle 19. This clutch is adapte d to en age the inner-periphery of the drivlng pu ley so that the spindle'may be rotated. i v In'order that the clutch may be moved mto and out of engagementwith the drivingpulley a hand operated lever 21 .is pivoted intermediate its ends in the cross head 22. The lower end of'this lever is formed into an inverted U. on the free ends of which are inwardly extending pins 60 and '61which. extend into the groove 62 formed in the peripher of the clutch 20. A The rlght end of the spindle 19 is provided with a chuck 25 forholding one end of a spool 46 upon which the wire is'to be woun and for causing the spool'torotate with1 tinge spindle. fight): other end of the spoo 1s supporte a sitio in 33 which is secured in t he $1 of rgfn'iilg pressed stud 36 slidably mounted in the uper end of the tail stock ,7, as shown in fn order that the position of the tail stock. 7 may be varied to accommodate supporting spools of difierent lengths tworods '30 and 31 sup orted by the bed of the lathe extend throug openings provided near the base of the tail stock. These rods and 31 guide the tail stock. when it is moved along the bed. The tail stockv7 ma be locked in adjusted position by means 0 a set screw 32.

The lateral movement of the positioning pm 33 and its supporting stud 36 with re spect to the tail stock 7 is controlled by a 100 pivoted bell crank lever 35. The short arm of thisl'everengages an opening near the end of the stud 36. This lever 35-is adapted to move the stud 36 and the positioning pin 33 ainst the action of the'coiled sprin' 37 wine maintains the positioning pm 8 inen ag'ement with one end ofthe spool4 6.-

n order that the resistance wiire may be' a spool and. with a difay there is provided a lead-11 fer'ent length of screw 40, one end of which is provided with a reduced portion 41 carrying a radially extending pin 42 which engages a slot 43 in theend of a shaft 17 The shaft 17 is journaled in the uprights 8 and 9, and is rotated by a gear -16 carried thereby and meshing with the spur ear 15 on the driving shaft. The other en of the leadscrew or guide is supported by a. spring pressed stud 44 mounted in the upper end of a supportmg block 45, which is slidably mounted upon the rod 31 The supporting block 45 after being properly positioned on the rod 31 may be locked in such position'by means of a set screw 46',

.A handwheel18' is mounted at one end of the shaft17 to provide means for rotating the spool 46 and the feed screw by hand.

Associated with the windin machine is a Wheatstone bridge circuit y means of which the resistance of the wire may be measured as it' isbeing wound upon the spool. This Wheatstone bridge circuit comprises the usual ratio arms a (Z and a 6 containing resistance coils 51 and and a third arm I) a which may comprise a standard coil 52 of the resistance to, which coils are to bewound by the winding machine with which the Wheatstone bridge circuit is associated. This standard coil is of known resistance. Instead of a standard coil, an adjustable resistance may be employed in the third arm of the bridge. Then when coils of a predetermined resistance are to be wound, the resistance of the third arm may beadjusted to this value. The fourth arm a d of the bridge is made up of the resistance wire being wound upon the s 001 and comprises an arm of unknown resistance. The usual source of current 53 and a switch'54 in circuit therewith are connected across the bridge points I) andd while the usual detecting mstrument such as a galvanometer 55dis connected across the bridge points a an 0. I

In order that the wire which 1 is being wound upon the s 001 may be properly connected with the ridge as the arm of unknown resistance thereof the bridge point (1 (see Fig. 3)- is connected by means ofa conductor 28 with a terminal 56 mounted upon but insulated from the upright 9 'of the head stock. A contact spring 57 connected at one end with this terminal .56 has its free end in frictionalv engagement with the periphery of a collector ring 26. The collector ring 26 is mounted upon the spindle 19 and rotates therewith. One endof a conductor 27 is connected with the collector ringl 26. The spool 46 may be provided wit two or more band terminals 47 depend-' ing upon the number of coils to be wound upon the same spool. The'free .end of the conductor 27 and the end of the resistance wire 49 are connected with the band terminal 47 provided at the left hand end of the spool. The bridge point a is connected by means of a conductor 29 with the rod 30.

This bridge point 0 is therefore in electrical engagement with the metallic lead screw 40.

The spool containing the resistance wire is supported below the lead screw 40. The resistance wire is therefore in electrical contact with the lead screw 40 as the wire is being wound on the spool 46. The fourth arm 0 d of the bridge may therefore be traced from the bridge point a of the Wheatstone bridge through conductor 29, the rod 30 and the lathe frame, the lead screw 40, resistance wire 49-, the. left hand band terminal 47, conducting strip 27, collector ring 26, contat'spring 57, terminal 56, and the conductor 28 to the bridge point (I.

The resistance wire is of comparatively that of the known element in arm b c of the bridge. 1

When starting to wind coils a standard coil of the resistance to which other coils are to be wound is connected in arm 5 c of the bridge and a spool 46 is mounted in the chuck 25 and the positioning in 3 3 of the lathe. The conductor 27 and t e end of the resistance wire 49 are then connected with gradually move to zero position. When the needlereaches zero position the resistance of the wire between the left hand terminal 47 and the lead-screw 40 equals that of. the

standard coil'52 connected in arm I) c of the bridge. Observingthe position of the needle the operator sto sthe further rotation of the spool by moving the clutch 20 out of enagement with the driving pulley 11. If

ut one coil is to be wound u on the spool the resistancewire is cut at the lead screw and the free end of the wire forming the coil is connected to the other band terminal on the spool. Usually when but one coil is to be wound upon a spool, the spool will have but two band terminals, one at each endthereof. However, if more than one coil is to be wound upon the same spool then when the needle of the galvanolneter indicates that suflicient wire has been wound upon the first coil the resistance wire is connected to the middle or second band terthe left hand band terminal 47 on the spool.

' bridge,

hand band terminal 47 tov short circuit the .coil between these terminals before starting the second coil. The operator may then proceed to wind the resistance wire on the second section of the spool continuously balancing the resistance; thereof against that of the standard coil. It will be seen therefore that it is not necessary to cut the wire before starting the second coil. The wire forming the loops may be cut and removed after all of the coils have been wound.

Frequently, it is necessary to wind upona support a large number of coils which vary in resistance." When it is desired to wind a large number of such coils upon thesame support, asample spool having coils of the requisite resistance wound thereon may be associated with the Wheatstone bridge circuit, as illustrated in Fig. 4. The first coil 52 of the sample resistance spool may form the third arm of known resistance for the while winding the first coil onto the supportin the windin machine. When the first-coil is wound to t e required-resistance as-determined by the balanced condition of the bridge, the resistance wire may be connected with the second hand terminal of the support. Then before proceeding to wind the second coil, the second coil 52 0f the sample resistance spool associated with the bridge is included in the third arm, so that .tioned in the windin machine.

the thirdarm is now made up of the first and second coils of the sample resistance spool. --The operator may then proceed to wind the second coil upon the sup rtposien the wire to the desire resistance has been wound into a secondcoil, as determined by the balanced condition of. the bridge, the wire is connected with the third band terminal. Then. before proceeding to wind thethird coil 52 u onthe support, I the third coil of'the s'amperesistance s 001 is added into the third arm of the bridge. So the windin proceeds, until all coils, each of the deslred resistance, are wound. It is to be noted that the resistance wire is continuous from the first to the last band terminal on the support upon which aplurality of coils are wound. t is also to be noted particularly that when winding the coils by this method, all wastage of resistance wire is eliminated. This method of including an additional coil the third arm of the bridge, before winding, another coil onto-"a multicoil support may, of course,'-be employed where some or all of the coils are to e of the same or ofdifferent. resistance values. i

The machine illustrated and described for winding resistance coils produces coils of the desired resistance, the turns of which are evenly wound u onthe spools. The wastage of wire is re need, to aminimum and'the measuring of theresistance of the coils by a separate 0 eration after winding is avoided thereby re ucing the handling of the coils and the number of operations required to produce coils of the proper resistance. The manufacture of such coils is thus facilitated. What is claimed is: I Q 1. A machine for winding resistance coils having in combination adjustable means for sup orting different sized spools upon which a p urality of series connected coils of resistance wire are to be wound, a pluralit of terminals associated with the spool to w ich the wire may be connected sequentially,

means for winding the wire upon the spool,

a screw-threadedmember arranged to rotate at a definite rate of speed with respect to said spool to guide the-w1re onto the latter and having electrical contact with the wire as it is wound upon the spool, and a detecting instrument for continuously, measuring sequentially the resistance of the wire between the respective terminals and said guide memlber as the wire is being wound upon the s 00 2; A machine for winding resistance coils having in'combination adjustable means for supporting different sized spools upon which resistance wire is to be wound, means for rotating the spool for coiling the resistance wire thereon, a rotating contact drum associated with the spool to which one end of the resistance wire 1s electrically connected, a

screw-threaded guide member in electrical contact with the wire as it is beingwound upon the spool, a Wheatstone bridge circuit having as one arm thereof an element of known resistance, circuit connections for including the resistance wire between the contact drum and element as an arm of unknown resistance in the brid e, a detecting instrument associated with t e brid e for comparing the resistance of the un nown arm' with that of the known element as'the wire is bein wound on the spool, and means for definite y increasing the known value of resistance in the first/mentioned arm of said Wheatstone bridge circuit.

3. A machine for winding resistance coils having in combination means for supporting a spoo upon which a plurality of series connected coils of resistance wire are to be wound, a plurality of. terminals to be se-" quentially connected with the resistance w re, means forwindin the-resistance wire upon the spool, a screw-t readed guide member in electrical contact with the wire as it is wound upon the spool, a Wheatstone' bridge circuit having the resistance wire between one terminal and the'guide member forming an armof unknown resistance thereof and havmg an element forming an arm of known resistance, a detecting instrument associated with the bridge forcojmparing the resistance of the unknown arm with that of the known element as the wire is being Wound on thespool, means for connecting said wire with another of said terminals, and means for addin a predetermined value of resistance to the inown element of said Wheatstone bridge.

4. A machine .for winding resistance coils comprising, in combination, adjustable means for supporting different sized spools upon which resistance wire is to be wound, end and intermediate terminals for the re sistance wire on each spool, means for winding the resistance wire upon the spool to proing a resistance of known value forming one. arm thereof, the wire bem wound on sand,

spool forming an arm of un own resistance, and means for definitely increasing the resistance of known value after completionof.

one coil on said spool to provide accurate measurement of the resistance of another coil subsequently wound thereon.

In witness whereof, I have hereunto subscribed my name.-

EDWIN N. LIGHTFOOT. 

